AusMT / surveys / KUTh Midlands 2009

KUTh Midlands 2009 BBMT

Magnetotelluric survey · Tasmania · Mineral Resources Tasmania

KUTh Exploration Pty Ltd, a subsidiary of KUTh Energy Ltd, acquired a broadband magnetotelluric survey over the Midlands of eastern Tasmania between 17 May and 4 July 2009, on the geothermal special exploration licences SEL26/2005 and SEL45/2007, to image the conductive structure around the inferred Lemont geothermal resource.

About this survey

KUTh Exploration Pty Ltd, a subsidiary of KUTh Energy Ltd, acquired a broadband magnetotelluric survey over the Midlands of eastern Tasmania between 17 May and 4 July 2009, on the geothermal special exploration licences SEL26/2005 and SEL45/2007, to image the conductive structure around the inferred Lemont geothermal resource. The sites span about 70 km north to south and 63 km east to west, from Epping Forest in the north to beyond Lake Leake in the east and Oatlands in the south west. Three of the eight site-code families form closely spaced lines: EWA, about 33 km roughly east to west at a median spacing of 1.0 km; NSA, about 52 km roughly north to south at 1.0 km; and NSB, about 46 km roughly north to south at 1.0 km. The other five families are sparser sites away from those lines, which the acquisition report describes as outliers collected to resolve three-dimensional structure. Moombarriga Geoscience Pty Ltd acquired the data for KUTh Exploration under Shane Evans. All but two soundings were remote referenced against another site of the same campaign, and the >INFO block of each file names the reference site it was processed against.

Recording used Phoenix Geophysics MTU-5A receivers with MTC-50 induction coils. The horizontal magnetic channels Bx and By and the electric channels Ex and Ey, on dipoles of about 90 m, were recorded at every site, and the vertical magnetic channel Bz at 90 of the 156 sites served here. Time series were written at three sample rates, 15, 150 and 2400 Hz, and notch filters were set for 50 Hz at every site. The acquisition report gives an average recording length of about 16 hours a site; the start and end times in the file headers give a median of 20.4 hours across the soundings served here. Transfer functions were estimated with the Phoenix SSMT suite, on the coherence-based rejection of Jones and Jodicke and the remote reference method of Gamble, Goubau and Clarke, and the cross powers were then edited by hand in MT-Editor.

This package serves 156 transfer functions as Phoenix cross-spectra EDI files. One hundred and fifty-one of them carry the full grid of 80 frequencies from 320 Hz to 0.00034 Hz, and the other five carry between 72 and 77 values drawn from that same grid. Three of the 156 are served here but withheld from the published products: at NSA031A, NSB006A and NSOC03A the magnetic sensors were laid rotated against the electric dipoles while the spectra declare a zero rotation, so the frame the spectra are stored in cannot be determined from the file.

Data origin. The files served here are 156 of the 158 members of TCZ_EDIs.zip, inside MT Data 2009 of Appendix 01 to the 2010 annual report on SEL26/2005 and SEL45/2007, Mineral Resources Tasmania report 10_6115, whose package sits at https://www.mrt.tas.gov.au/mrtdoc/tasxplor/download/10_6115 and whose modelling and processing components are MRT webdoc records 90549, 90550 and 90582. The lodgement is open file because the tenements were surrendered, and it is served under Creative Commons Attribution 3.0 Australia, the licence Mineral Resources Tasmania applies to its data releases. The two members held back are EWA013A.edi, an earlier edit of the sounding served as NSA013A, and NSOA04A.edi, a re-edit of a 2008 sounding served in another package. The acquisition report states that the time series were written at three sample rates and delivered to KUTh; no 2009 raw time series is present in the Mineral Resources Tasmania web store, and whether the agency holds them offline is unknown.

Data and downloads

Stations (153)

Contributors and organisations

Organisation

Mineral Resources Tasmania

Licence

CC BY 3.0 AU

Instruments

Phoenix Geophysics MTU-5A
Phoenix Geophysics MTC-50

Processing

Phoenix SSMT

Funding

KUTh Exploration Pty Ltd

Publications

Ostersen T C H (2021). Geoelectric Structure of the Tasmanian Lithosphere from Multi-Scale Magnetotelluric Data. PhD thesis, University of Tasmania. 10.25959/100.00037925

Ostersen T C H, Reading A M, Cracknell M J, Roach M, Duffett M L, McNeill A, Bishop J R, Brand K E, Thiel S, Heinson G (2024). Low resistivity anomalies in the upper crust of the Midlands of Tasmania from combined magnetotelluric datasets. Exploration Geophysics 55(5) 545-561. 10.1080/08123985.2024.2385099

Identifiers and provenance

Machine-readable survey record · catalogue schema mtcat 2.0